Light-emitting diodes, light-emitting diode arrays and related devices

ABSTRACT

Light-emitting diodes (LEDs), LED arrays, and related devices are disclosed. An LED device includes a first LED chip and a second LED chip mounted on a submount with a light-altering material in between. The light-altering material may include at least one of a light-reflective material and/or a light-absorbing material. Individual wavelength conversion elements may be arranged on each of the first and second LED chips. The light-altering material may improve the contrast between the first and second LED chips as well as between the individual wavelength conversion elements. LED devices may include submounts in modular configurations where LED chips may be mounted on adjacent submounts to form an LED array. Each LED chip of the LED array may be laterally separated from at least one other LED chip by a same distance and a light-altering material may be arranged around the LED array.

FIELD OF THE DISCLOSURE

The present disclosure relates to solid-state lighting devices includinglight-emitting diodes, light-emitting diode arrays, and devicesincorporating light-emitting diodes or light-emitting diode arrays.

BACKGROUND

Solid-state lighting devices such as light-emitting diodes (LEDs) areincreasingly used in both consumer and commercial applications.

Advancements in LED technology have resulted in highly efficient andmechanically robust light sources with a long service life. Accordingly,modern LEDs have enabled a variety of new display applications and arebeing increasingly utilized for general illumination applications, oftenreplacing incandescent and fluorescent light sources.

LEDs are solid-state devices that convert electrical energy to light andgenerally include one or more active layers of semiconductor material(or an active region) arranged between oppositely doped n-type andp-type layers. When a bias is applied across the doped layers, holes andelectrons are injected into the one or more active layers where theyrecombine to generate emissions such as visible light or ultravioletemissions. An LED chip typically includes an active region that may befabricated, for example, from silicon carbide, gallium nitride, galliumphosphide, aluminum nitride, gallium arsenide-based materials, and/orfrom organic semiconductor materials. Photons generated by the activeregion are initiated in all directions.

LEDs have been widely adopted in various illumination contexts, forbacklighting of liquid crystal display (LCD) systems (e.g., as asubstitute for cold cathode fluorescent lamps), and for sequentiallyilluminated LED displays. Applications utilizing LED arrays includevehicular headlamps, roadway illumination, light fixtures, and variousindoor, outdoor, and specialty contexts. Desirable characteristics ofLED devices include high luminous efficacy, long lifetime, and widecolor gamut. In such LED array applications, it may be desirable to haveLEDs spaced more closely together in order for the array to appear as auniform emission area when all LEDs are electrically activated, orturned on. However, when some LEDs of the LED array are turned off, orelectrically deactivated, it may be challenging to provide good contrastbetween LEDs in an on-state relative to LEDs in an off-state. This isdue in part to the omnidirectional character of LED emissions, which canmake it difficult to prevent emissions of one LED from significantlyoverlapping with emissions of another LED of an array, thereby resultingin crosstalk or light spillage between emissions of adjacent LEDs.Significant overlap between beams emitted by adjacent LEDs tends toimpair the effective resolution of a LED array device; however, attemptsto segregate light beams may result in undesirable non-illuminated or“dark” zones between adjacent LEDs, and may also impair brightness ofaggregate emissions. It may be challenging to provide LED array devicesthat address the foregoing issues in combination.

The art continues to seek improved LEDs and solid-state lighting deviceshaving reduced optical losses and providing desirable illuminationcharacteristics capable of overcoming challenges associated withconventional lighting devices.

SUMMARY

Aspects disclosed herein relate to light-emitting diodes (LEDs), LEDarrays, and related devices. An LED device includes a first LED chip anda second LED chip mounted on a submount with a light-altering materialbetween the first LED chip and the second LED chip. The light-alteringmaterial may include at least one or more of a light-reflective materialand a light-absorbing material. Individual wavelength conversionelements may be arranged on each of the first LED chip and the secondLED chip. The light-altering material may improve contrast between thefirst LED chip and the second LED chip as well as between the individualwavelength conversion elements. LED devices may include submounts withat least one electrically conductive anode or cathode path that isdiscontinuous on a surface of the submount where LED chips are mounted.LED devices may include submounts in modular configurations where LEDchips may be mounted on adjacent submounts to form an LED array. EachLED chip of the LED array may be laterally separated from at least oneother LED chip by a same distance, and a light-altering material may bearranged around the LED array.

In one aspect, an LED device comprises: a submount; a first LED chip anda second LED chip on a surface of the submount, wherein the first LEDchip is laterally separated from the second LED chip on the surface; afirst wavelength conversion element registered with the first LED chip,wherein the first wavelength conversion element comprises a firstsuperstrate and a first lumiphoric material that is arranged between thefirst superstrate and the first LED chip; a second wavelength conversionelement registered with the second LED chip, wherein the secondwavelength conversion element comprises a second superstrate and asecond lumiphoric material that is arranged between the secondsuperstrate and the second LED chip; and a first light-altering materialarranged between the first LED chip and the second LED chip on thesubmount, wherein the light-altering material comprises a firstlight-reflective material and a first light-absorbing material. Incertain embodiments, the first light-reflective material and the firstlight-absorbing material are interspersed in a same binder. The firstlight-reflective material may comprise a weight percent that is in arange of about 10% to about 90% of a total weight of the light-alteringmaterial. The first light-absorbing material may comprise a weightpercent that is in a range of about greater than 0% to about 15% of atotal weight of the light-altering material. The first light-alteringmaterial may further be arranged between the first wavelength conversionelement and the second wavelength conversion element. In certainembodiments, the LED device may further comprise a second light-alteringmaterial arranged between the first wavelength conversion element andthe second .wavelength conversion element. The second light-alteringmaterial may comprise a different amount of the first light-absorbingmaterial than the first light-altering material. In certain embodiments,a gap is formed in the first light-altering material between the firstLED chip and the second LED chip. The gap may extend through the firstlight-altering material to the submount. In certain embodiments, the LEDdevice further comprises a second light-altering material in the gap.The second light-altering material may comprise at least one of thefirst light-absorbing material and a second light-reflective material.In certain embodiments, the first light-altering material is arrangedaround an entire perimeter of the first LED chip and around an entireperimeter of the second LED chip.

In another aspect, an LED device comprises: a submount comprising afirst face and a second face that opposes the first face; a first LEDchip mounting region on the first face, the first chip LED mountingregion comprising a first anode and a first cathode; a first anode bondpad and a first cathode bond pad on the first face; a first electricallyconductive anode path between the first anode and the first anode bondpad; a first electrically conductive cathode path between the firstcathode and the first cathode bond pad; wherein one of the firstelectrically conductive anode path or the first electrically conductivecathode path is continuous along the first face, and the other of thefirst electrically conductive anode path or the first electricallyconductive cathode path is discontinuous along the first face. Incertain embodiments, the one of the first electrically conductive anodepath or the first electrically conductive cathode path that isdiscontinuous along the first face comprises a portion that extendsalong the second face. In certain embodiments, the portion that extendsalong the second face is electrically connected to one or moreelectrically conductive vias that extend through the submount. The LEDdevice may further comprise: a second anode bond pad on the second facethat is electrically connected to the first anode bond pad on the firstface; and a second cathode bond pad on the second face that iselectrically connected to the first cathode bond pad on the first face.

In another aspect, an LED device comprises: a submount comprising afirst face, a second face opposing the first face, and a first lateraledge; and a plurality of LED chips mounted on the first face of thesubmount; wherein each LED chip of the plurality of LED chips islaterally separated from at least one other LED chip of the plurality ofLED chips by a first distance; and wherein at least one LED chip of theplurality of LED chips is laterally separated from the first lateraledge by a second distance that is in a range of about 40% to 60% of thefirst distance. The submount may further comprise: a second lateral edgethat is adjacent the first lateral edge; and a first plurality of anodebond pads and a first plurality of cathode bond pads both arranged onthe first face along the second lateral edge. In certain embodiments,the second lateral edge is substantially perpendicular to the firstlateral edge. The submount may further comprise: a third lateral edgethat is substantially perpendicular to the first lateral edge andsubstantially parallel to the second lateral edge; a second plurality ofanode bond pads and a second plurality of cathode bond pads botharranged on the first face along the third lateral edge. In certainembodiments, the second distance is in a range of about 45% to about 55%of the first distance. In certain embodiments, the second distance is ina range of about 20 microns (μm) to about 120 μm. In certainembodiments, a lighting device comprises a plurality of LED devices aspreviously described, wherein the submount of each LED device of theplurality of LED devices is in contact with a submount of at least oneother LED device of the plurality or LED devices.

In another aspect, an LED device comprises: a first plurality of LEDchips mounted on a first submount; a second plurality of LED chipsmounted on a second submount; and a light-altering material that iscontinuous on the first submount and the second submount. In certainembodiments, the light-altering material is arranged around an entireperimeter of the first plurality of LED chips and the second pluralityof LED chips. In certain embodiments, the first plurality of LED chipsand the second plurality of LED chips form an LED array and each LEDchip of the LED array is laterally separated from at least one other LEDchip of the LED array by a first distance. In certain embodiments, eachLED chip of the first plurality of LED chips and each LED chip of thesecond plurality of LED chips comprises a face that is distal to theeither the first submount or the second submount, and the light-alteringmaterial does not cover the face. In certain embodiments, each LED chipof the first plurality of LED chips and each LED chip of the secondplurality of LED chips comprises at least one of a growth substrate or acarrier substrate. In certain embodiments, the first submount is incontact with the second submount.

In another aspect, an LED device comprises a submount comprising a firstface and a second face that opposes the first face; a first LED chip anda second LED chip on the first face, wherein the first LED chip islaterally separated from the second LED chip on the first face; a firstwavelength conversion element registered with the first LED chip,wherein the first wavelength conversion element comprises a firstsuperstrate and a first lumiphoric material that is arranged between thefirst superstrate and the first LED chip; a second wavelength conversionelement registered with the second LED chip, wherein the secondwavelength conversion element comprises a second superstrate and asecond lumiphoric material that is arranged between the secondsuperstrate and the second LED chip; and a light-altering materialarranged between the first LED chip and the second LED chip and whereina portion of the light-altering material extends to a lateral edge ofthe first face. In certain embodiments, the light-altering materialcomprises a light-absorbing material. In certain embodiments, thelight-altering material comprises a light-reflective material.

In another aspect, any of the foregoing aspects, and/or various separateaspects and features as described herein, may be combined for additionaladvantage. Any of the various features and elements as disclosed hereinmay be combined with one or more other disclosed features and elementsunless indicated to the contrary herein.

Those skilled in the art will appreciate the scope of the presentdisclosure and realize additional aspects thereof after reading thefollowing detailed description of the preferred embodiments inassociation with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the disclosure, andtogether with the description serve to explain the principles of thedisclosure.

FIG. 1A is a top view of an LED device with a plurality of LED chipsarranged on a submount.

FIG. 1B is a side cross-sectional view taken along the section line ofthe LED device of FIG. 1A.

FIG. 2A is top view of an LED device with a plurality of LED chipsarranged on a submount as previously described.

FIG. 2B is a line plot of an illumination profile when some of the LEDchips of FIG. 2A are electrically activated, and some of the LED chipsof FIG. 2A are electrically deactivated.

FIG. 3A is a side cross-sectional view of an LED device with a pluralityof LED chips arranged on a submount according to embodiments disclosedherein.

FIG. 3B is a side cross-sectional view of an LED device with a pluralityof LED chips arranged on a submount according to embodiments disclosedherein.

FIG. 3C is a plot representing contrast measurements for severalconfigurations of the LED device of FIG. 3A.

FIG. 4 is a plot representing illuminance and contrast ratiomeasurements of the configurations of FIG. 3C at various drive currents.

FIG. 5 is a side cross-sectional view of an LED device with a pluralityof LED chips arranged on a first surface of a submount according toembodiments disclosed herein.

FIG. 6 is a side cross-sectional view of an LED device with a pluralityof LED chips arranged on a first surface of a submount according toembodiments disclosed herein.

FIG. 7 is a side cross-sectional view of an LED device with a pluralityof LED chips arranged on a first surface of a submount according toembodiments disclosed herein.

FIG. 8 is a side cross-sectional view of an LED device with a pluralityof LED chips arranged on a first surface of a submount according toembodiments disclosed herein.

FIG. 9 is a top view of an LED package including a plurality of LEDchips on a first surface of a submount according to embodimentsdisclosed herein.

FIG. 10A is a top view of an LED package including a plurality of LEDchips on a first surface of a submount according to embodimentsdisclosed herein.

FIG. 10B is a bottom view of the LED package of FIG. 10A.

FIG. 11A is a top view of a submount configured for an individuallycontrollable LED array according to embodiments disclosed herein.

FIG. 11B is a bottom view of the submount of FIG. 11A.

FIG. 12 is top view of an LED device that includes a first submount anda second submount that are positioned adjacent to one another.

FIG. 13A is a top view of a submount configured for an individuallycontrollable LED array according to embodiments disclosed herein.

FIG. 13B is a bottom view of the submount of FIG. 13A.

FIG. 14 is top view of a lighting device that includes a plurality ofsubmounts that are positioned adjacent to one another.

FIG. 15 is a top view of a lighting device that includes the pluralityof submounts and the first plurality of LED chips, the second pluralityof LED chips, and the third plurality of LED chips of FIG. 14 as well asa light-altering material.

DETAILED DESCRIPTION

The embodiments set forth below represent the necessary information toenable those skilled in the art to practice the embodiments andillustrate the best mode of practicing the embodiments. Upon reading thefollowing description in light of the accompanying drawing figures,those skilled in the art will understand the concepts of the disclosureand will recognize applications of these concepts not particularlyaddressed herein. It should be understood that these concepts andapplications fall within the scope of the disclosure and theaccompanying claims.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present disclosure. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element such as a layer, region, orsubstrate is referred to as being “on” or extending “onto” anotherelement, it can be directly on or extend directly onto the other elementor intervening elements may also be present. In contrast, when anelement is referred to as being “directly on” or extending “directlyonto” another element, there are no intervening elements present.Likewise, it will be understood that when an element such as a layer,region, or substrate is referred to as being “over” or extending “over”another element, it can be directly over or extend directly over theother element or intervening elements may also be present. In contrast,when an element is referred to as being “directly over” or extending“directly over” another element, there are no intervening elementspresent. It will also be understood that when an element is referred toas being “connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present.

Relative terms such as “below” or “above” or “upper” or “lower” or“horizontal” or “vertical” may be used herein to describe a relationshipof one element, layer, or region to another element, layer, or region asillustrated in the Figures. It will be understood that these terms andthose discussed above are intended to encompass different orientationsof the device in addition to the orientation depicted in the Figures.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “includes,” and/or “including” when used herein specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms used herein should be interpreted ashaving a meaning that is consistent with their meaning in the context ofthis specification and the relevant art and will not be interpreted inan idealized or overly formal sense unless expressly so defined herein.

Aspects disclosed herein relate to light-emitting diodes (LEDs), LEDarrays, and related devices. An LED device includes a first LED chip anda second LED chip mounted on a submount with a light-altering materialbetween the first LED chip and the second LED chip. The light-alteringmaterial may include at least one or more of a light-reflective materialand a light-absorbing material. Individual wavelength conversionelements may be arranged on each of the first LED chip and the secondLED chip. The light-altering material may improve contrast between thefirst LED chip and the second LED chip as well as between the individualwavelength conversion elements. LED devices may include submounts withat least one electrically conductive anode or cathode path that isdiscontinuous on a surface of the submount where LED chips are mounted.LED devices may include submounts in modular configurations where LEDchips may be mounted on adjacent submounts to form an LED array. EachLED chip of the LED array may be laterally separated from at least oneother LED chip by a same distance, and a light-altering material may bearranged around the LED array.

An LED chip typically comprises an active LED structure or region thatcan have many different semiconductor layers arranged in different ways.The fabrication and operation of LEDs and their active structures aregenerally known in the art and are only briefly discussed herein. Thesemiconductor layers of the active LED structure can be fabricated usingknown processes with a suitable process being fabrication using metalorganic chemical vapor deposition. The semiconductor layers of theactive LED structure can comprise many different layers and generallycomprise an active layer sandwiched between n-type and p-type oppositelydoped epitaxial layers, all of which are formed successively on a growthsubstrate. It is understood that additional layers and elements can alsobe included in the active LED structure, including but not limited to:buffer layers, nucleation layers, super lattice structures, un-dopedlayers, cladding layers, contact layers, current-spreading layers, andlight extraction layers and elements. The active layer can comprise asingle quantum well, a multiple quantum well, a double heterostructure,or super lattice structures.

The active LED structure can be fabricated from different materialsystems, with some material systems being Group III nitride-basedmaterial systems. Group III nitrides refer to those semiconductorcompounds formed between nitrogen and the elements in Group III of theperiodic table, usually aluminum (Al), gallium (Ga), and indium (In).Gallium nitride (GaN) is a common binary compound. Group III nitridesalso refer to ternary and quaternary compounds such as aluminum galliumnitride (AlGaN), indium gallium nitride (InGaN), and aluminum indiumgallium nitride (AlInGaN). For Group III nitrides, silicon (Si) is acommon n-type dopant and magnesium (Mg) is a common p-type dopant.Accordingly, the active layer, n-type layer, and p-type layer mayinclude one or more layers of GaN, AlGaN, InGaN, and AlInGaN that areeither undoped or doped with Si or Mg for a material system based onGroup III nitrides. Other material systems include silicon carbide(SiC), organic semiconductor materials, and other Group III-V systemssuch as gallium phosphide (GaP), gallium arsenide (GaAs), and relatedcompounds.

The active LED structure may be grown on a growth substrate that caninclude many materials, such as sapphire, SiC, aluminum nitride (AlN),GaN, with a suitable substrate being a 4H polytype of SiC, althoughother SiC polytypes can also be used including 3C, 6H, and 15Rpolytypes. SiC has certain advantages, such as a closer crystal latticematch to Group III nitrides than other substrates and results in GroupIII nitride films of high quality. SiC also has a very high thermalconductivity so that the total output power of Group III nitride deviceson SiC is not limited by the thermal dissipation of the substrate.Sapphire is another common substrate for Group III nitrides and also hascertain advantages including being lower cost, having establishedmanufacturing processes, and having good light transmissive opticalproperties.

Different embodiments of the active LED structure can emit differentwavelengths of light depending on the composition of the active layerand n-type and p-type layers. In certain embodiments, the active LEDstructure emits a blue light in a peak wavelength range of approximately430 nanometers (nm) to 480 nm. In other embodiments, the active LEDstructure emits green light in a peak wavelength range of 500 nm to 570nm. In other embodiments, the active LED structure emits red light in apeak wavelength range of 600 nm to 650 nm. The LED chip can also becovered with one or more lumiphors or other conversion materials, suchas phosphors, such that at least some of the light from the LED chippasses through the one or more phosphors and is converted to one or moredifferent wavelengths of light. In certain embodiments, the LED chipemits a generally white light combination of light from the active LEDstructure and light from the one or more phosphors. The one or morephosphors may include yellow (e.g., YAG:Ce), green (LuAg:Ce), and red(Ca_(i-x-y)Sr_(x)Eu_(y)AlSiN₃) emitting phosphors, and combinationsthereof.

In certain embodiments, a wavelength conversion element includes one ormore lumiphors or a lumiphoric material that is disposed on asuperstrate. The term “superstrate” as used herein refers to an elementplaced on an LED chip with a lumiphoric material between the superstrateand the LED chip. The term “superstrate” is used herein, in part, toavoid confusion with other substrates that may be part of thesemiconductor light emitting device, such as a growth or carriersubstrate of the LED chip or a submount of an LED package. The term“superstrate” is not intended to limit the orientation, location, and/orcomposition of the structure it describes. In certain embodiments, thesuperstrate may be composed of, for example, sapphire, SiC, silicone,and/or glass (e.g., borosilicate and/or fused quartz). The superstratemay be patterned to enhance light extraction from the LED chip asdescribed in commonly-assigned U.S. Provisional Application No.62/661,359 entitled “Semiconductor Light Emitting Devices IncludingSuperstrates With Patterned Surfaces” which is hereby incorporated byreference herein. The superstrate may also be configured as described incommonly-assigned U.S. Patent Application Publication No. 2018/0033924,also incorporated by reference herein. The superstrate may be formedfrom a bulk substrate which is optionally patterned and then singulated.In certain embodiments, the patterning of the superstrate may beperformed by an etching process (e.g., wet or dry etching). In certainembodiments, the patterning of the superstrate may be performed byotherwise altering the surface, such as by a laser or saw. In certainembodiments, the superstrate may be thinned before or after thepatterning process is performed. The lumiphoric material may then beplaced on the superstrate by, for example, spraying and/or otherwisecoating the superstrate with the lumiphoric material. The superstrateand the lumiphoric material may be attached to the LED chip using, forexample, a layer of transparent adhesive. In certain embodiments, whenthe superstrate is attached to the LED chip, a portion of thetransparent adhesive is positioned at least partially between lateraledges of the LED chip. In certain embodiments, a single wavelengthconversion element may cover multiple LED chips. In other embodiments,individual wavelength conversion elements may be registered withindividual LED chips.

The present disclosure can include LED chips having a variety ofgeometries, such as vertical geometry or lateral geometry. A verticalgeometry LED chip typically includes an anode and cathode on opposingsides of the active LED structure. A lateral geometry LED chip typicallyincludes an anode and a cathode on the same side of the active LEDstructure that is opposite a substrate, such as a growth substrate or acarrier substrate. In certain embodiments, a lateral geometry LED chipmay be mounted on a submount of an LED package such that the anode andcathode are on a face of the active LED structure that is opposite thesubmount. In this configuration, wire bonds may be used to provideelectrical connections with the anode and cathode. In other embodiments,a lateral geometry LED chip may be flip-chip mounted on a submount of anLED package such that the anode and cathode are on a face of the activeLED structure that is adjacent to the submount. In this configuration,electrical traces or patterns may be provided on the submount forproviding electrical connections to the anode and cathode of the LEDchip. In a flip-chip configuration, the active LED structure isconfigured between the substrate of the LED chip and the submount forthe LED package. Accordingly, light emitted from the active LEDstructure may pass through the substrate in a desired emissiondirection. In certain embodiments, the flip-chip LED chip may beconfigured as described in commonly-assigned U.S. Patent ApplicationPublication No. 2017/0098746, which is hereby incorporated by referenceherein.

Embodiments of the disclosure are described herein with reference tocross-sectional view illustrations that are schematic illustrations ofembodiments of the disclosure. As such, the actual thickness of thelayers can be different, and variations from the shapes of theillustrations as a result, for example, of manufacturing techniquesand/or tolerances, are expected. For example, a region illustrated ordescribed as square or rectangular can have rounded or curved features,and regions shown as straight lines may have some irregularity. Thus,the regions illustrated in the figures are schematic and their shapesare not intended to illustrate the precise shape of a region of a deviceand are not intended to limit the scope of the disclosure.

FIG. 1A is a top view of an LED device 10 with a plurality of LED chips12-1 to 12-6 arranged on a submount 14. While the LED device 10 isillustrated with six LED chips 12-1 to 12-6, any number of LED chips arepossible. In certain embodiments, LED devices according to embodimentsdisclosed herein may include an array of LED chips with as few as twoLED chips or as many as one hundred LED chips or more. The submount 14can be formed of many different materials with an exemplary materialbeing electrically insulating. Suitable materials include, but are notlimited to ceramic materials such as aluminum oxide or alumina, AlN, ororganic insulators like polyimide (PI) and polyphthalamide (PPA). Inother embodiments, the submount 14 can comprise a printed circuit board(PCB), sapphire, Si or any other suitable material. For PCB embodiments,different PCB types can be used such as a standard FR-4 PCB, a metalcore PCB, or any other type of PCB. FIG. 1B is a side cross-sectionalview taken along the section line of the LED device 10 of FIG. 1A. Asillustrated, the LED chip 12-1 and the LED chip 12-2 are laterallyseparated on a first surface 16 of the submount 14. A first wavelengthconversion element 18-1 is registered with the first LED chip 12-1, anda second wavelength conversion element 18-2 is registered with thesecond LED chip 12-2. The first wavelength conversion element 18-1 mayinclude a first lumiphoric material 20-1 and a first superstrate 22-1,and the second wavelength conversion element 18-2 may include a secondlumiphoric material 20-2 and a second superstrate 22-2. In certainembodiments, the first lumiphoric material 20-1 and the secondlumiphoric material 20-2 are respectively disposed on the firstsuperstrate 22-1 and the second superstrate 22-2. Notably, in thisconfiguration, the lumiphoric materials 20-1, 20-2 are not located inthe space between the LED chips 12-1, 12-2 on the submount 14, therebyreducing light conversion and improving contrast between the LED chips12-1, 12-2. Light emitted from an active region of an LED structure orlight that is converted by a lumiphoric material is typicallyomnidirectional in nature. Accordingly, a portion of light emitted fromeither the first LED chip 12-1 or converted by the first lumiphoricmaterial 20-1 may travel laterally toward the second LED chip 12-2. Inthis regard, some light from the first LED chip 12-1 may bleed over tothe relative position of the second LED chip 12-2 and decrease contrastbetween the two LED chips 12-1, 12-2. Additionally, at least some of thelateral light from one of the LED chips 12-1, 12-2 may be lost toabsorption within the other of the LED chips 12-1, 12-2. In someapplications, it may be desirable for a combined emission area betweenthe two LED chips 12-1, 12-2 to appear as a uniform emission area.However, in other applications, such as those where each of the LEDchips 12-1, 12-2 can be electrically activated (turned on) orelectrically de-activated (turned off) independently of each other, thecontrast between the LED chips 12-1, 12-2 may be lower than what isdesired.

FIG. 2A is top view of an LED device 24 with a plurality of LED chips26-1 to 26-6 arranged on a submount 28 as previously described. FIG. 2Bis a line plot of an illumination profile when the LED chips 26-2, 26-4,and 26-5 are electrically activated, and the LED chips 26-1, 26-3, and26-6 are electrically deactivated. The y-axis of the plot is luminancein candela per square centimeter (cd/cm²) and the x-axis is the relativedistance in millimeters (mm) a sensor moves across the plurality of LEDchips 26-1 to 26-6 in a direction as indicated by the dashed line 29 ofFIG. 2A. In the plot of FIG. 2B, a first high luminance area 30indicates the relative position of the LED chip 26-2, and a secondbroader high luminance area 32 indicates the relative position of theLED chips 26-4, 26-5. A luminance valley 34 is located between the highluminance areas 30 and 32 and indicates the relative position of the LEDchip 26-3. As shown in the plot, even though the LED chip 26-3 iselectrically deactivated, an elevated luminance is measured due tolateral emissions and cross-talk from the LED chips 26-2, 26-4, and26-5. In this regard, contrast between the electrically activated LEDchips 26-2, 26-4, 26-5 and the electrically de-activated LED chips 26-1,26-3, and 26-6 is lower that what is desired for certain applications.

In certain embodiments, a light-emitting device includes at least twoLED chips that are laterally separated on a submount. A separatewavelength conversion element may be registered with each LED chip. Toimprove contrast between adjacent LED chips, a light-altering materialmay be arranged between the adjacent LED chips. The light-alteringmaterial may be adapted for dispensing, or placing, and may include manydifferent materials including light-reflective materials that reflect orredirect light, light-absorbing materials that absorb light, andmaterials that act as a thixotropic agent. As used herein, the term“light-reflective” refers to materials or particles that reflect,refract, or otherwise redirect light. For light-reflective materials,the light-altering material may include at least one of fused silica,fumed silica, titanium dioxide (TiO₂), or metal particles suspended in abinder, such as silicone or epoxy. In certain embodiments, thelight-reflecting materials comprise a generally white color. Forlight-absorbing materials, the light-altering material may include atleast one of carbon, silicon, or metal particles suspended in a binder,such as silicon or epoxy. In certain embodiments, the light-absorbingmaterials comprise a generally black color. The light-reflectivematerials and the light-absorbing materials may comprise nanoparticles.In certain embodiments, the light-altering material includes bothlight-reflective materials and light-absorbing material suspended in abinder. A weight ratio of the light-reflective material to the bindermay comprise a range of about 1:1 to about 2:1. A weight ratio of thelight-absorbing material to the binder may comprise a range of about1:400 to about 1:10. In certain embodiments, a total weight of thelight-altering material includes any combination of the binder, thelight-reflective material, and the light-absorbing material. In someembodiments, the binder may comprise a weight percent that is in a rangeof about 10% to about 90% of the total weight of the light-alteringmaterial; the light-reflective material may comprise a weight percentthat is in a range of about 10% to about 90% of the total weight of thelight-altering material; and the light-absorbing material may comprise aweight percent that is in a range of about 0% to about 15% of the totalweight of the light-altering material. In further embodiments, thelight-absorbing material may comprise a weight percent that is in arange of about greater than 0% to about 15% of the total weight of thelight-altering material. In further embodiments, the binder may comprisea weight percent that is in a range of about 25% to about 70% of thetotal weight of the light-altering material; the light-reflectivematerial may comprise a weight percent that is in a range of about 25%to about 70% of the total weight of the light-altering material; and thelight-absorbing material may comprise a weight percent that is in arange of about 0% to about 5% of the total weight of the light-alteringmaterial. In further embodiments, the light-absorbing material maycomprise a weight percent that is in a range of about greater than 0% toabout 5% of the total weight of the light-altering material. In certainembodiments, the light-altering material may comprise a generally whitecolor to reflect and redirect light. In other embodiments, thelight-altering material may comprise a generally opaque or black colorfor absorbing light and increasing contrast of an LED package. Thelight-altering material can be dispensed or deposited in place using anautomated dispensing machine where any suitable size and/or shape can beformed. The light-altering material may have a viscosity configured tobe dispensed around a perimeter of an LED chip and surface tension willkeep the light-altering material off of a primary emitting surface ofthe LED chip. Additionally, the light-altering material may wick inbetween adjacent LED chips that are separated by narrow lateraldistances.

FIG. 3A is a side cross-sectional view of an LED device 36 with aplurality of LED chips 38-1 to 38-2 arranged on a submount 40 accordingto embodiments disclosed herein. A first wavelength conversion element42-1 that includes a first lumiphoric material 44-1 and a firstsuperstrate 46-1 is registered with the first LED chip 38-1. A secondwavelength conversion element 42-2 that includes a second lumiphoricmaterial 44-2 and a second superstrate 46-2 is registered with thesecond LED chip 38-2. A light-altering material 48 is arranged betweenthe first LED chip 38-1 and the second LED chip 38-2 on the submount 40.In certain embodiments, the light-altering material 48 extends from afirst surface 49 of the submount 40 to a height that is at least levelwith the LED chips 38-1, 38-2. In further embodiments, thelight-altering material 48 extends from the first surface 49 to a heightthat is at least level with the lumiphoric materials 44-1, 44-2. Instill further embodiments, the light-altering material 48 extends fromthe first surface 49 to a height that is at least level with thewavelength conversion elements 42-1, 42-2. In certain embodiments, thelight-altering material 48 includes light-reflective particles andlight-absorbing particles that are interspersed and suspended in a samebinder.

FIG. 3B is a side cross-sectional view of an additional embodiment ofthe LED device 36 of FIG. 3A. As previously described, the plurality ofLED chips 38-1 to 38-2 are arranged on the submount 40, the firstwavelength conversion element 42-1 that includes the first lumiphoricmaterial 44-1 and the first superstrate 46-1 is registered with thefirst LED chip 38-1, and the second wavelength conversion element 42-2that includes the second lumiphoric material 44-2 and the secondsuperstrate 46-2 is registered with the second LED chip 38-2. In FIG.3B, a first light-altering material 48A and a second light-alteringmaterial 48B are arranged between the first LED chip 38-1 and the secondLED chip 38-2 on the submount 40. In certain embodiments, a combinationof the first and second light-altering materials 48A, 48B extends fromthe first surface 49 of the submount 40 to a height that is at leastlevel with the LED chips 38-1, 38-2. In further embodiments, thecombination of the first and second light-altering materials 48A, 48Bextends from the first surface 49 to a height that is at least levelwith the lumiphoric materials 44-1, 44-2. In still further embodiments,the combination of the first and second light-altering materials 48A,48B extends from the first surface 49 to a height that is at least levelwith the wavelength conversion elements 42-1, 42-2. The first and secondlight-altering materials 48A, 48B may be formed separately from oneanother by sequential dispensing or other deposition steps.

In certain embodiments, the first and second light-altering materials48A, 48B includes light-reflective particles and light-absorbingparticles that are interspersed and suspended in a same binder. Incertain embodiments, the first light-altering material 48A comprises adifferent amount of light-reflective particles and/or light-absorbingparticles than the second light-altering material 48B. For example, thefirst light-altering material 48A may comprise a lower amount oflight-absorbing particles than the second light-altering material 48B.In certain embodiments, the first light-altering material 48A comprisesno light-absorbing materials. In certain embodiments, the secondlight-altering material 48B may comprise at least two times the amountof light-absorbing particles as the first light-altering material 48A.In further embodiments, the second light-altering material 48B maycomprise at least five times, or in a range of five times to ten timesor more the amount of light-absorbing particles as the firstlight-altering material 48A. In this regard, the first light-alteringmaterial 48A is configured to reflect more light between the first LEDchip 38-1 and the second LED chip 38-2 while the second light-alteringmaterial 48B is configured to provide more contrast between the firstwavelength conversion element 42-1 and the second wavelength conversionelement 42-2. Depending on the application, the order may be reversed inother embodiments such that the second light-altering material 48Bcomprises a lower amount of light-absorbing particles than the firstlight-altering material 48A. The amounts may differ in a similar manneras previously described. In this regard, the first light-alteringmaterial 48A may provide higher contrast between the first LED chip 38-1and the second LED chip 38-2 while the second light-altering material48B provides higher reflectivity between the first wavelength conversionelement 42-1 and the second wavelength conversion element 42-2. In otherembodiments, only one of the first light-altering material 48A and thesecond light altering material 48B comprises light-reflective and/orlight absorbing particles while the other is substantially clear.

FIG. 3C is a plot representing contrast measurements for severalconfigurations of the LED device 36 of FIG. 3A. In a firstconfiguration, labeled “Sample 1” in FIG. 3C, the light-alteringmaterial 48 of FIG. 3A includes a weight ratio of TiO₂ (light-reflectiveparticles) to a silicone binder of about 1:1. In a second configuration,labeled “Sample 2” in FIG. 3C, the light-altering material 48 of FIG. 3Aincludes the same composition as Sample 1 with an addition of carbonparticles (light-absorbing particles) in a weight ratio of about 1:25 ofthe binder. In a third configuration, labeled “Sample 3” in FIG. 3C, thelight-altering material 48 of FIG. 3A includes the same composition asSample 1 with an addition of carbon particles (light-absorbingparticles) in a weight ratio of about 1:12.5 of the binder. For each ofthe Samples 1, 2, and 3, the light-reflective particles and thelight-absorbing particles (only Samples 2 and 3) are interspersed andsuspended in the same binder of silicone. The y-axis in FIG. 3Crepresents arbitrary units of a contrast ratio as defined by a ratio ofluminance between an electrically activated LED chip (on) and anadjacent LED chip that is electrically deactivated (off). A highercontrast ratio indicates a higher delta between the measured luminanceof the electrically activated LED chip compared to the electricallydeactivated LED chip. The x-axis represents various configurations forthe LED chip (or die) spacing for each of the samples in microns (μm).As shown by the plot, the configurations of Sample 2 and Sample 3demonstrated notably higher contrast ratios for all LED chip spacings.

The addition of light-absorbing particles between LED chips can lead toa nominal decrease in brightness. However, this can be compensated forby increasing a drive current to the LED chips. FIG. 4 is a plotrepresenting illuminance and contrast ratio measurements of the Samples1, 2, and 3 of FIG. 3C at various drive currents. The x-axis representsthe die spacing (in μm) and drive current (in amps) for each of thesamples. The y-axis represents both illuminance in candela per squaremillimeter (cd/mm²) and the contrast ratio. As expected, the illuminancevalues are lower for the Samples 2 and 3 that include light-absorbingparticles. However, the drive current for the Samples 2 and 3 may beincreased to increase the illuminance values and the contrast ratiosremain notable higher than Sample 1 that does not includelight-absorbing particles.

In certain embodiments, different configurations of light-reflectivematerials and light-absorbing materials may be provided. For example, alight-altering material that includes a first light-reflective materialmay be provided between two LED chips and a gap may be formed thatextends through the light-altering material to a submount on which theLED chips are mounted. In certain embodiments, a second light-reflectivematerial may be provided in the gap. In certain embodiments, alight-absorbing material may be provided in the gap. In still furtherembodiments, both of the second light-reflective material and thelight-absorbing material may be provided in the gap. In this manner,further improvements to the illuminance and contrast ratio of adjacentLED chips may be realized.

FIG. 5 is a side cross-sectional view of an LED device 50 with aplurality of LED chips 52-1 to 52-2 arranged on a first surface 54 of asubmount 56 according to embodiments disclosed herein. The LED device 50additionally includes: a first wavelength conversion element 58-1 with afirst lumiphoric material 60-1 and a first superstrate 62-1; a secondwavelength conversion element 58-2 with a second lumiphoric material60-2 and a second superstrate 62-2; and a light-altering material 64 aspreviously described. In FIG. 5, a portion of the light-alteringmaterial 64 is removed or never deposited to form a gap 66 in thelight-altering material 64 between a first LED chip 52-1 and a secondLED chip 52-2. In certain embodiments, the gap 66 extends through thelight-altering material 64 to the first surface 54 of the submount 56.The gap 66 may provide an index of refraction delta with thelight-altering material 64. In this manner, light traveling laterallybetween the LED chips 52-1, 52-2 and the wavelength conversion elements58-1, 58-2 may be redirected in a desired direction, thereby improvingoverall illuminance levels and contrast between the LED chips 52-1,52-2.

FIG. 6 is a side cross-sectional view of an LED device 68 with aplurality of LED chips 70-1 to 70-2 arranged on a first surface 72 of asubmount 74 according to embodiments disclosed herein. The LED device 68additionally includes: a first wavelength conversion element 76-1 with afirst lumiphoric material 78-1 and a first superstrate 80-1; a secondwavelength conversion element 76-2 with a second lumiphoric material78-2 and a second superstrate 80-2; a first light-altering material 82;and a gap 84 as previously described. In FIG. 6, a second light-alteringmaterial 86 is formed on the first light-altering material 82. Thesecond light-altering material 86 may be formed by selective thin filmdeposition, such as through a mask, in the gap 84. The secondlight-altering material 86 may include at least one of alight-reflective-material and/or a light-absorbing material aspreviously described. In certain embodiments, the second light-alteringmaterial 86 comprises a layer of reflective metal and the firstlight-altering material 82 comprises light-reflective particles. Inother embodiments, the second light-altering material 86 compriseslight-absorbing particles and the first light-altering material 82comprises light-reflective particles. In other embodiments, the secondlight-altering material 86 comprises light-reflective particles and thefirst light-altering material 82 comprises light-absorbing particles. Instill further embodiments, the first light-altering material 82 and thesecond light-altering material 84 may both include light-reflectiveparticles and light-absorbing particles in differing amounts.

FIG. 7 is a side cross-sectional view of an LED device 88 with aplurality of LED chips 90-1 to 90-2 arranged on a first surface 92 of asubmount 94 according to embodiments disclosed herein. The LED device 88additionally includes: a first wavelength conversion element 96-1 with afirst lumiphoric material 98-1 and a first superstrate 100-1; a secondwavelength conversion element 96-2 with a second lumiphoric material98-2 and a second superstrate 100-2; and a first light-altering material102 as previously described. In FIG. 7, a second light-altering material104 fills a gap (66 of FIG. 5) formed in the first light-alteringmaterial 102. The second light-altering material 104 may be formed bydispensing or depositing in the gap (66 of FIG. 5). The secondlight-altering material 104 may include at least one of alight-reflective-material and/or a light-absorbing material aspreviously described. In certain embodiments, the second light-alteringmaterial 104 comprises light-absorbing particles and the firstlight-altering material 102 comprises light-reflective particles. Inother embodiments, the second light-altering material 104 compriseslight-reflective particles and the first light-altering material 102comprises light-absorbing particles. In still further embodiments, thefirst light-altering material 102 and the second light-altering material104 may both include light-reflective particles and light-absorbingparticles in differing amounts. In certain embodiments, the secondlight-altering material 104 extends above the first light-alteringmaterial 102 in a direction away from the first surface 92 of thesubmount 94. In this regard, more light traveling laterally may beredirected or absorbed between the LED chips 90-1, 90-2, thereby furtherimproving contrast.

FIG. 8 is a side cross-sectional view of an LED device 106 with aplurality of LED chips 108-1 to 108-2 arranged on a first surface 110 ofa submount 112 according to embodiments disclosed herein. The LED device106 additionally includes: a first wavelength conversion element 114-1with a first lumiphoric material 116-1 and a first superstrate 118-1; asecond wavelength conversion element 114-2 with a second lumiphoricmaterial 116-2 and a second superstrate 118-2; and a firstlight-altering material 120 as previously described. In FIG. 8, a secondlight-altering material 122 and a third light-altering material 124fills a gap (66 of FIG. 5) formed in the first light-altering material120. The second light-altering material 122 is similar to the secondlight-altering material 86 of FIG. 5, and the third light-alteringmaterial 124 is similar to the second light-altering material 104 ofFIG. 7. In certain embodiments, the first light-altering material 120includes light-reflective particles, the second light-altering material122 includes a layer of reflective metal, and the third light-alteringmaterial 124 includes light-absorbing particles. In other embodiments,the first light-altering material 120 includes light-absorbing particlesand the third light-altering material 124 includes light-reflectiveparticles. In still other embodiments, the first light-altering material120, the second light-altering material 122, and the thirdlight-altering material 124 may all include both light-reflectiveparticles and light-absorbing particles, but in differing amounts.

Embodiments as disclosed herein may be particularly suited for LEDdevices or packages that include a plurality of LED chips that form anLED array on a submount. Anode and cathode bond pads may be provided onthe submount that are configured to receive an external electricalconnection, such as wirebonds. Electrically conductive anode paths andelectrically conductive cathode paths are configured to electricallyconnect the anode and cathode bond pads with the plurality of LED chips.In certain embodiments, the anode and cathode bond pads are on a samesurface of the submount on which the plurality of LED chips are mounted.In other embodiments, the anode and cathode bond pads are on an oppositesurface of the submount from the plurality of LED chips.

FIG. 9 is a top view of an LED package 126 including a plurality of LEDchips 128-1 to 128-3 on a first surface 130, or face, of a submount 132according to embodiments disclosed herein. A first bond pad 134-1 and asecond bond pad 134-2 are provided on the first surface 130 of thesubmount 132 and laterally spaced away from the plurality of LED chips128-1 to 128-3 on the first surface 130. Depending on the configuration,the first bond pad 134-1 may comprise either a cathode bond pad or ananode bond pad and the second bond pad 134-2 may comprise the other ofthe cathode bond pad or the anode bond pad. A light-altering material136 as previously described is arranged around an entire perimeter of afirst LED chip 128-1, around an entire perimeter of a second LED chip128-2, and around an entire perimeter of a third LED chip 128-3. Incertain embodiments, individual wavelength conversion elements 138-1 to138-3 are separately registered with each of the plurality of LED chips128-1 to 128-3. The light-altering material 136 is additionally arrangedaround an entire perimeter of each of the wavelength conversion elements138-1 to 138-3. In certain embodiments, at least a portion of thelight-altering material 136 extends to a lateral edge of the firstsurface 130 of the submount 132. In FIG. 9, the light-altering material136 extends to three of the four lateral edges of the submount 132. Inthis manner, the light-altering material 136 does not extend to thefourth lateral edge of the submount 132 that is adjacent the first bondpad 134-1 and the second bond pad 134-2. Accordingly, the first bond pad134-1 and the second bond pad 134-2 are uncovered by the light-alteringmaterial 136. In certain embodiments, the light-altering material 136 isconfigured to redirect or reflect laterally-emitting light from the LEDchips 128-1 to 128-3 or the wavelength conversion elements 138-1 to138-3 toward a desired emission direction. In certain embodiments, thelight-altering material 136 may block or absorb at least a portion ofany laterally-emitting light from the LED chips 128-1 to 128-3 or thewavelength conversion elements 138-1 to 138-3. The light-alteringmaterial 136 may partially cover the submount 132 outside of where theLED chips 128-1 to 128-3 are located. In this regard, the light-alteringmaterial 136 may cover portions of the submount that extend from thefirst bond pad 134-1 and the second bond pad 134-2 to the LED chips128-1 to 128-3, while leaving the first bond pad 134-1 and the secondbond pad 134-2 uncovered. A first electrically conductive path 140-1electrically connects the first bond pad 134-1 to at least one of theplurality of LED chips 128-1 to 128-3 and a second electricallyconductive path 140-2 electrically connects the second bond pad 134-2 toat least one of the plurality of LED chips 128-1 to 128-3. In FIG. 9,the electrically conductive paths 140-1, 140-2 are on the first surface130 of the submount 132 and barely visible outside of the light-alteringmaterial 136. In this regard, the electrically conductive paths 140-1,140-2 comprise traces that extend on the first surface 130 under thelight-altering material 136. In other embodiments, the light-alteringmaterial 136 entirely covers the electrically conductive paths 140-1,140-2.

FIG. 10A is a top view of an LED package 142 including a plurality ofLED chips 144-1 to 144-3 on a first surface 146 of a submount 148according to embodiments disclosed herein. The LED package 142 mayfurther include a light-altering material 150 and a plurality ofwavelength conversion elements 152-1 to 152-3 as previously described.In FIG. 10A, the light-altering material 150 covers substantially all ofthe first surface 146 of the submount 148. In certain embodiments, atleast a portion of the light-altering material 150 extends to alllateral edges of the first surface 146 of the submount 148. FIG. 10B isa bottom view of the LED package 142 of FIG. 10A. A second surface 154of the submount 148 that opposes the first surface 146 of FIG. 10A isvisible. A first bond pad 156-1 and a second bond pad 156-2 aspreviously described are arranged on the second surface 154 of thesubmount 148. In this manner, the LED package 142 may be configured tobe surface mounted to a board (not shown) such that the bond pads 156-1,156-2 align with electrical traces or pads on the board. As with the LEDdevice 126 of FIG. 9, a first electrically conductive path 158-1electrically connects the first bond pad 156-1 to at least one of theplurality of LED chips 152-1 to 152-3 (FIG. 10A), and a secondelectrically conductive path 158-2 electrically connects the second bondpad 156-2 to at least one of the plurality of LED chips 152-1 to 152-3(FIG. 10A). However, in FIG. 10B, the electrically conductive paths158-1, 158-2 extend from the second surface 154 of the submount 148 tothe first surface 146. In that regard, the electrically conductive paths158-1, 158-2 may comprise electrically conductive vias that extendthrough the submount 148.

As previously described, embodiments as disclosed herein may beparticularly suited for LED devices or packages that include a pluralityof LED chips that form an LED array on a submount. In certainembodiments, the LED chips of the LED array are individuallycontrollable in a manner such that each of the LED chips may beindependently turned on and off. Improved contrast ratios between on andoff LED chips in the LED array may be desirable in applications whereemission directions and patterns from a LED device are adjustable. Suchapplications include automotive lighting such as adaptable light sourcesfor headlights, aerospace lighting, general illumination, video screendisplays, and pixelated LED arrays. In order to provide an LED devicewith a plurality of independently controllable LED chips, a submount mayinclude multiple anode and cathode bond pads with multiple electricallyconductive anode and cathode paths. In certain embodiments, at least oneof the electrically conductive anode and cathode paths is discontinuousalong a first face of a submount where the LED chips are mounted. Inthis regard, a portion of the electrically conductive anode and cathodepaths may extend along a second face of the submount that is oppositethe first face. Embodiments as disclosed herein may describe particularconfigurations of anodes and cathodes, anode and cathode bond pads, andelectrically conductive anode and cathode paths. It is understood thatin other configurations the polarities may be reversed by renamingelements described with anode configurations as cathodes and vice versa.

FIG. 11A is a top view of a submount 160 configured for an individuallycontrollable LED array according to embodiments disclosed herein. FIG.11B is a bottom view of the submount 160 of FIG. 11A. The submount 160comprises a first face 162 and a second face 164 that opposes the firstface 162. A plurality of LED chip mounting regions 166-1 to 166-3 are onthe first face as indicated by the dashed lines in FIG. 11A. Forillustrative purposes, the location of the plurality of LED chipmounting regions 166-1 to 166-3 relative to the second face 164 areshown in dashed lines in FIG. 11B. For simplicity, only the LED chipmounting regions 166-1 to 166-3 are labeled. However, the submount 160as illustrated is configured with LED chip mounting regions forthirty-six individual LED chips and the following description may beapplicable to all of the LED chip mounting regions. Additionally,embodiments as disclosed herein are applicable to any number of LED chipmounting regions. A first LED chip mounting region 166-1 includes afirst anode 168-1 and a first cathode 170-1; a second LED chip mountingregion 166-2 includes a second anode 168-2 and a second cathode 170-2; athird LED chip mounting region 166-3 includes a third anode 168-3 and athird cathode 170-3; and so on. By way of an example, the first anode168-1 and the first cathode 170-1 are configured to electrically contacta corresponding anode and cathode of an LED chip (not shown) that may bemounted in the first mounting region 166-1. A plurality of first anodebond pads 172-1 to 172-3 and a plurality of first cathode bond pads174-1 to 174-3 are arranged on the first face 162 of the submount 160.For simplicity in FIG. 11A, only the first anode bond pads 172-1 to172-3 and the first cathode bond pads 174-1 to 174-3 are labeled. Inorder to individually control each of the LED chips that will be mountedin the plurality of LED chip mounting regions 166-1 to 166-3, each LEDchip mounting region 166-1 to 166-3 is electrically connected with aunique pair of one of the first anode bond pads 172-1 to 172-3 and oneof the first cathode bond pads 174-1 to 174-3. A plurality ofelectrically conductive anode paths 176-1 to 176-3 and a plurality ofelectrically conductive cathode paths 178-1 to 178-3 are used to makethese connections. For example, the electrically conductive anode path176-1 extends between and is continuous with the first anode 168-1 andthe first anode bond pad 172-1; and the electrically conductive cathodepath 178-2 (FIG. 11B) extends between and is continuous with the firstcathode 170-1 and the second cathode bond pad 174-2. In this manner,electrical connections with the first anode bond pad 172-1 and thesecond cathode bond pad 174-2 may be used to electrically control an LEDchip mounted to the first LED chip mounting region 166-1. In a similarmanner, electrical connections with the first anode bond pad 172-1 andthe first cathode bond pad 174-1 may be used to electrically control anLED chip mounted to the third LED chip mounting region 166-3.Accordingly, the third LED chip mounting region 166-3 shares theelectrically conductive anode path 176-1 and the first anode bond pad172-1 with the first LED chip mounting region 166-1. However, the thirdLED chip mounting region 166-3 is electrically connected with the firstcathode bond pad 174-1 by way of the electrically conductive cathodepath 178-1.

As illustrated in FIGS. 11A and 11B, the plurality of electricallyconductive cathode paths 178-1 to 178-3 are discontinuous on the firstface 162 of the submount 160. In this manner, the plurality ofelectrically conductive cathode paths 178-1 to 178-3 extend through thesubmount 160 to the second face 164 of the submount, and at least aportion of the plurality of electrically conductive cathode paths 178-1to 178-3 extend on the second face 164. By way of example, theelectrically conductive cathode path 178-1 includes a first electricallyconductive via 180-1 that extends from the first cathode bond pad 174-1on the first face 162 to a second cathode bond pad 182-1 on the secondface 164. A portion of the electrically conductive cathode path 178-1extends along the second face 164 to an area below the third LED chipmounting region 166-3. The electrically conductive cathode path 178-1further includes a second via 180-2 that extends to the third cathode170-3 on the first face 162. In this manner, each one of the pluralityof first anode bond pads 172-1 to 172-3 is electrically connected to acorresponding one of a plurality of second anode bond pads 184-1 to184-3 through the submount 160 by vias, and each one of the plurality offirst cathode bond pads 174-1 to 174-3 has a corresponding one of theplurality of second cathode bond pad 182-1 to 182-3 that are alsoelectrically connected through the submount 160 by vias. Accordingly,the submount 160 is configured to receive external electricalconnections on either of the first face 162 (e.g. by wire bonds) or thesecond face 164 (e.g. by corresponding electrical traces on a board).

As illustrated in FIGS. 11A and 11B, each of the plurality ofelectrically conductive anode paths 176-1 to 176-3 and each of theplurality of electrically conductive cathode paths 178-1 to 178-3 areconfigured to be electrically connected with more than one of theplurality of LED chip mounting regions 166-1 to 166-3. However, incertain embodiments, each LED chip mounting region 166-1 to 166-3comprises a unique combination of a particular electrically conductiveanode path 176-1 to 176-3 and a particular electrically conductivecathode path 178-1 to 178-3. By sharing electrically conductive anode orcathode paths to control different LED chips, a total number ofelectrically conductive anode or cathode paths may be reduced whilestill maintaining independent control of each LED chip that is mountedon the submount 160. In certain embodiments, the total number ofelectrically conductive anode and cathode paths may be less than a totalnumber of LED chips. For example, FIGS. 11A and 11B illustrate asubmount configured with thirty-six different LED chip mounting areasthat are configured to receive and independently control thirty-six LEDchips with only twelve electrically conductive anode paths and onlytwelve electrically conductive cathode paths. By having a reduced numberof electrically conductive anode or cathode paths, electricalconnections on the submount may be simplified. Accordingly, the firstsurface 162 of the submount 160 may have space for an area 186 thatincludes identification or other information, including a quick response(QR) code, a bar code, or alphanumeric information.

In certain embodiments, the portions of the electrically conductivecathode paths 178-1 to 178-3 on the second face 164 include expandeddimensions. In this manner, an increased surface area of the second face164 is covered by the electrically conductive cathode paths 178-1 to178-3. In certain embodiments, the electrically conductive cathode paths178-1 to 178-3 include one or more layers of metal or metal alloys thatcomprise good thermal conductivity. In this regard, the portions of theelectrically conductive cathode paths 178-1 to 178-3 on the second face164 may additionally serve as heat sinks or heat spreaders to assistwith heat dissipation away from LED chips mounted on the first face 162.In certain embodiments, between about 60% and 95% of the total surfacearea of the second face 164 is covered by the electrically conductivecathode paths 178-1 to 178-3. In further embodiments, between about 70%and 80% of the total surface area of the second face 164 is covered bythe electrically conductive cathode paths 178-1 to 178-3. In stillfurther embodiments, between about 70% and 75% of the total surface areaof the second face 164 is covered by the electrically conductive cathodepaths 178-1 to 178-3.

In certain embodiments, a plurality of LED chips of an LED array may bemounted on a submount. Each LED chip of the plurality of LED chips islaterally separated from at least one other LED chip of the plurality ofLED chips by a first distance, and at least one LED chip of theplurality of LED chips is laterally separated from a first lateral edgeof the submount by a second distance that is in a range of about 40% toabout 60%, or about 45% to 55%, or about 50% of the first distance. Inthis regard, multiple submounts may be positioned adjacent to eachother, and LED chips on the multiple submounts form an LED array wherethe first distance is maintained across the multiple submounts withinthe LED array. In certain embodiments, the second distance is in a rangeof about 20 μm to about 120 μm. In further embodiments, the seconddistance is in a range of about 40 μm to about 100 μm. In still furtherembodiments, the second distance is in a range 50 μm to about 90 μm.Other dimensions for the second distance are possible provided thedimensions are close enough that when multiple submounts are positionedadjacent to one another, the lateral separation of LED chips across themultiple submounts appears uniform. Additionally, a plurality of anodebond pads and a plurality of cathode bond pads may be arranged along oneor more lateral edges of a submount. When multiple submounts arearranged together, the plurality of anode and cathode bond pads may bearranged on one or more lateral edges of the submounts that aredifferent from lateral edges where the submounts are joined together.

FIG. 12 is top view of an LED device 188 that includes a first submount190-1 and a second submount 190-2 that are positioned adjacent to oneanother. The first submount 190-1 and the second submount 190-2 aresimilar to the submount 160 of FIGS. 11A and 11B. The first submount190-1 includes a plurality of first LED chip mounting areas 192-1 to192-3 and the second submount 190-2 includes a plurality of second LEDchip mounting areas 194-1 to 194-3. As before, only some of the firstLED chip mounting areas 192-1 to 192-3 and only some of the second LEDchip mounting areas 194-1 to 194-3 are numbered for simplicity. Each ofthe first LED chip mounting areas 192-1 to 192-3 are laterally separatedfrom at least one other of the first LED chip mounting areas 192-1 to192-3 by a first distance, and at least one of the first LED chipmounting areas 192-1 to 192-3 is laterally separated from a firstlateral edge 196 of the first submount 190-1 by a second distance thatis about half of the first distance. In particular embodiments, thesecond distance is in a range of about 40% to about 60%, or about 45% to55%, or about 50% of the first distance. Other dimensions for the seconddistance are possible provided the dimensions are close enough that whenthe submounts 190-1, 190-2 are positioned adjacent to one another, thelateral separation of subsequently-mounted LED chips across thesubmounts 190-1, 190-2 appears uniform. In a similar manner, each of thesecond LED chip mounting areas 194-1 to 194-3 are laterally separated bythe same first distance, and at least one of the second LED chipmounting areas 194-1 to 194-3 is separated from the first lateral edgeby the same second distance. In this regard, when the first submount190-1 and the second submount 190-2 are aligned at the lateral edge 196,the first distance is maintained between the first LED chip mountingareas 192-1 to 192-3 and the second LED chip mounting areas 194-1 to194-3 that are closest to the lateral edge 196. In certain embodiments,the first distance may include a range of about 0.04 mm to about 1 mm.In further embodiments, the first distance may include a range of about0.04 mm to about 0.5 mm, or a range of about 0.04 mm to about 0.2 mm, ora range of about 0.04 to about 0.12 mm. In certain embodiments, LEDchips to be mounted on the submounts 190-1, 190-2 comprise a longestdimension of about 0.7 mm and the first distance is in a range of about0.05 mm to about 0.1 mm.

FIG. 13A is a top view of a submount 198 configured for an individuallycontrollable LED array according to embodiments disclosed herein. FIG.13B is a bottom view of the submount 198 of FIG. 13A. The submount 198comprises a first face 200 and a second face 202 that opposes the firstface 200. A plurality of LED chip mounting regions 204-1 to 204-3 are onthe first face 200 as indicated by the dashed lines in FIG. 13A. Asillustrated, the submount 198 is configured with nine LED chip mountingregions, however only the LED chip mounting regions 204-1 to 204-3 arelabeled. A first LED chip mounting region 204-1 includes a first anode206-1 and a first cathode 208-1; a second LED chip mounting region 204-3includes a second anode 206-2 and a second cathode 208-2; a third LEDchip mounting region 204-3 includes a third anode 206-3 and a thirdcathode 208-3; and so on. By way of an example, the first anode 206-1and the first cathode 208-1 are configured to electrically contact acorresponding anode and cathode of an LED chip (not shown) that may bemounted in the first mounting region 204-1. In certain embodiments, theLED chip mounting regions 204-1 to 204-3 are aligned along a firstlateral edge 210 of the submount 198 with a spacing as previouslydescribed. The submount 198 additionally includes a second lateral edge212 and a third lateral edge 214 that are both adjacent the firstlateral edge 210. In certain embodiments, the second lateral edge 212and the third lateral edge 214 each are substantially perpendicular withthe first lateral edge 210 on opposing sides of the submount 198.

A first anode bond pad 216 and a first cathode bond pad 218 are botharranged on the first face 200 along the second lateral edge 212, and asecond anode bond pad 220 and a second cathode bond pad 222 are botharranged on the first face 200 along the third lateral edge 214. Forsimplicity in FIG. 13A, additional anode bond pads and cathode bond padsare not labeled, however, a plurality of first anode and cathode bondpads may be arranged along the second lateral edge 212 and a pluralityof second anode and cathode bond pads may be arranged along the thirdlateral edge 214 for additional LED chip mounting regions. In thismanner, anode and cathode bond pads may be aligned along opposinglateral edges to provide individual control to LED chips mounted on thesubmount 198. In other embodiments, anode and cathode bond pads may bealigned along a single edge of the submount 198. In order toindividually control each of the LED chips that will be mounted in theLED chip mounting regions 204-1 to 204-3, each LED chip mounting region204-1 to 204-3 is electrically connected with a unique pair of eitherthe first anode bond pad 216 or the second anode bond pad 220 and eitherthe first cathode bond pad 218 or the second cathode bond pad 222. Afirst electrically conductive anode path 224 extends between and iscontinuous with the first anode 206-1 and the first anode bond pad 216.A first electrically conductive cathode path 226 extends between and iscontinuous with the first cathode bond pad 218 and both of the firstcathode 208-1 and the second cathode 208-2. A second electricallyconductive anode path 228 extends between and is continuous with thesecond anode bond pad 220 and both of the second anode 206-2 and thethird anode 206-3. Finally, a second electrically conductive cathodepath 230 extends between and is continuous with the second cathode bondpad 222 and the third cathode 208-3. In this manner, an LED chip mountedto mounting region 204-1 may be electrically activated by electricallyaddressing the first anode bond pad 216 and the first cathode bond pad218. An LED chip mounted to the mounting region 204-2 may beelectrically activated by electrically addressing the second anode bondpad 220 and the first cathode bond pad 218. An LED chip mounted tomounting region 204-3 may be electrically activated by electricallyaddressing the second anode bond pad 220 and the second cathode bond pad222. As with previous embodiments, depending on the configuration, thepolarities may be reversed such that elements previously referred to asvarious types of anode elements may be cathode elements and elementspreviously referred to as anode elements may be cathode elements.Additionally, the first surface 200 may have space for an area 232 thatincludes identification or other information, including a quick response(QR) code, a bar code, or alphanumeric information.

In contrast to previous embodiments, the second face 202, or thebackside of the submount 198, is free of electrically conductive paths.Accordingly, the entire second face 202 may be covered with a thermallyconductive material for heat dissipation. In other embodiments, at leasta portion of the second face 202 may be covered with a thermallyconductive material. In still other embodiments, the second face 202 maynot include additional materials, rather the second face 202 may beconfigured to be directly mounted to another surface.

FIG. 14 is top view of a lighting device 233 that includes a pluralityof submounts 234-1 to 234-3 that are positioned adjacent to one another.The first submount 234-1, the second submount 234-2, and the thirdsubmount 234-3 are similar to the submount 198 of FIGS. 13A and 13B. Afirst plurality of LED chips 236 are mounted on the first submount234-1, a second plurality of LED chips 238 are mounted on the secondsubmount 234-2, and a third plurality of LED chips 240 are mounted onthe third submount 234-3. For simplicity, only some of the LED chips236, 238, 240 are labeled, however there are twenty-seven total LEDchips 236, 238, 240 in FIG. 14. In other embodiments, the LED chips 236,238, 240 may include any number of LED chips. The first plurality of LEDchips 236, the second plurality of LED chips 238, and the thirdplurality of LED chips 240 collectively form an LED array that extendsacross the plurality of submounts 234-1 to 234-3. As with previousembodiments, each LED chip 236, 238, 240 of the LED array is spacedapart from at least one other LED chip 236, 238, 240 of the LED array bya first distance that is consistent for the LED array across theplurality of submounts 234-1 to 234-3.

According to embodiments disclosed herein, an LED device may include aplurality of submounts, each of which include a plurality of LED chips.As previously described, the plurality of LED chips on each of thesubmounts collectively forms an LED array across the plurality ofsubmounts. In this manner, additional elements for the LED device mayalso be formed that extend across the plurality of submounts. Forexample, one or more light-altering materials as previously describedmay be continuous on and across each of the plurality of submounts. Theone or more light-altering materials may be arranged around an entireperimeter of the LED array as well as in between individual LED chips ofthe LED array.

FIG. 15 is a top view of a lighting device 242 that includes theplurality of submounts 234-1 to 234-3 and the first plurality of LEDchips 236, the second plurality of LED chips 238, and the thirdplurality of LED chips 240 of FIG. 14. The LED chips 236, 238, and 240collectively form an LED array. The lighting device 242 additionallyincludes a light-altering material 244 as previously described. Thelight-altering material 244 is continuous on and across the firstsubmount 234-1, the second submount 234-2, and the third submount 234-3.In certain embodiments, the light-altering material 244 is formed afterthe plurality of submounts 234-1 to 234-3 are mounted or joinedtogether. In other embodiments, each of the submounts 234-1 to 234-3 mayinclude a portion of the light-altering material 244 before they aremounted or joined together. In this manner, the portions of thelight-altering material 244 on each of the submounts 234-1 to 234-3collectively form the light-altering material 244 that is continuousacross the plurality of submounts 234-1 to 234-3. In certain embodimentswhere the submounts 234-1 to 234-3 include a portion of thelight-altering material 244 before they are mounted or joined together,an additional application of light-altering material may be needed tofill in any gaps in the light-altering material 244 after the submounts234-1 to 234-3 are assembled together. In certain embodiments, thelight-altering material 244 is arranged around an entire perimeter ofthe first plurality of LED chips 236, the second plurality of LED chips238, and the third plurality of LED chips 240. Additionally, thelight-altering material 244 may be arranged between individual LED chipsof the first plurality of LED chips 236, the second plurality of LEDchips 238, and the third plurality of LED chips 240. Each LED chip ofthe first, second, and third plurality of LED chips 236, 238, 240includes a face that is distal to the corresponding submount 234-1 to234-3 on which it is mounted, and in certain embodiments, thelight-altering material 244 does not cover the face. In certainembodiments, each LED chip of the first, second, and third plurality ofLED chips 236, 238, 240 includes at least one of a growth substrate or acarrier substrate. As with previous embodiments, each of the LED chips236, 238, 240 may include a wavelength conversion element as previouslydescribed, and the light-altering material 244 further does not cover aface of each wavelength conversion element that is distal to thecorresponding submount 234-1 to 234-3 on which it is mounted. Each ofthe plurality of submounts 234-1 to 234-3 may be in contact with atleast one other submount of the plurality of submounts 234-1 to 234-3.As previously described, each of the LED chips 236, 238, 240 may bearranged on the plurality of submounts 234-1 to 234-3 such that each LEDchip 236, 238, 240 is laterally separated from at least one other LEDchip 236, 238, 240 of the LED array by a first distance that isconsistent through the LED array. In this manner, the lighting device242 includes an LED array of individually addressable LED chips 236,238, 240 with improved contrast as different ones of the LED chips 236,238, 240 are electrically activated and electrically de-activated.

While the preceding figures illustrate anode and cathode bond padsaligned along opposing edges of a submount, the anode and cathode bondpads may be aligned along a single edge of the submount in certainembodiments. Additionally, multiple submounts with anode and cathodebond pads aligned along a single edge may be mounted or joined togetherto form a larger array as previously described. In certain embodiments,a lighting device includes at least a first submount with anode andcathode bond pads aligned along a single edge that is joined or mountedadjacent to at least a second submount with anode and cathode bond padsaligned along opposing edges.

Those skilled in the art will recognize improvements and modificationsto the preferred embodiments of the present disclosure. All suchimprovements and modifications are considered within the scope of theconcepts disclosed herein and the claims that follow.

What is claimed is:
 1. A light emitting diode (LED) device comprising: asubmount; a first LED chip and a second LED chip on a surface of thesubmount, wherein the first LED chip is laterally separated from thesecond LED chip on the surface; a first wavelength conversion elementregistered with the first LED chip; a second wavelength conversionelement registered with the second LED chip; a first light-alteringmaterial arranged between the first LED chip and the second LED chip onthe submount, wherein the first light-altering material is furtherarranged between the first wavelength conversion element and the secondwavelength conversion element, wherein the first light-altering materialcomprises a first light-reflective material and a first light-absorbingmaterial, and wherein a gap is formed entirely through the firstlight-altering material to a surface of the submount that is between thefirst LED chip and the second LED chip; and a second light-alteringmaterial that is in the gap such that at least a portion of the firstlight-altering material is uncovered by the second light-alteringmaterial.
 2. The LED device of claim 1, wherein the firstlight-reflective material and the first light-absorbing material areinterspersed in a same binder.
 3. The LED device of claim 2, wherein thefirst light-reflective material comprises a weight percent that is in arange from 10% to 90% of a total weight of the first light-alteringmaterial.
 4. The LED device of claim 2, wherein the firstlight-absorbing material comprises a weight percent that is in a rangefrom greater than 0% to 15% of a total weight of the firstlight-altering material.
 5. The LED device of claim 1, wherein thesecond light-altering material is arranged between the first wavelengthconversion element and the second wavelength conversion element.
 6. TheLED device of claim 1, wherein the second light-altering materialcomprises a different amount of the first light-absorbing material thanthe first light-altering material.
 7. The LED device of claim 1, whereinthe second light-altering material comprises at least one of the firstlight-absorbing material or a second light-reflective material.
 8. TheLED device of claim 1, wherein the first light-altering material isarranged around an entire perimeter of the first LED chip and around anentire perimeter of the second LED chip.
 9. The LED device of claim 1,wherein the second light-altering material comprises a thickness abovethe submount that is greater than a thickness of the firstlight-altering material.
 10. The LED device of claim 1, wherein thesecond light-altering material is arranged to extend above a top surfaceof the first wavelength conversion element.
 11. The LED device of claim1, wherein the first wavelength conversion element comprises a firstsuperstrate and a first lumiphoric material that is arranged between thefirst superstrate and the first LED chip, and the second wavelengthconversion element comprises a second superstrate and a secondlumiphoric material that is arranged between the second superstrate andthe second LED chip.
 12. A light emitting diode (LED) device comprising:a submount comprising a first face and a second face that opposes thefirst face; a first LED chip and a second LED chip on the first face,wherein the first LED chip is laterally separated from the second LEDchip on the first face; a first wavelength conversion element registeredwith the first LED chip; a second wavelength conversion elementregistered with the second LED chip; a first light-altering materialarranged between the first LED chip and the second LED chip and arrangedbetween the first wavelength conversion element and the secondwavelength conversion element, wherein the first light-altering materialis arranged around an entire perimeter of the first LED chip and thesecond LED chip, wherein a portion of the first light-altering materialextends to a lateral edge of the first face, and wherein a gap is formedentirely through the first light-altering material to a surface of thesubmount that is between the first LED chip and the second LED chip; anda second light-altering material that is in the gap such that at least aportion of the first light-altering material is uncovered by the secondlight-altering material.
 13. The LED device of claim 12 wherein thefirst light-altering material comprises a light-absorbing material. 14.The LED device of claim 12 wherein the first light-altering materialcomprises a light-reflective material.
 15. The LED device of claim 12,wherein the second light-altering material is arranged to extend above atop surface of the first wavelength conversion element.
 16. The LEDdevice of claim 12, wherein the first wavelength conversion elementcomprises a first superstrate and a first lumiphoric material that isarranged between the first superstrate and the first LED chip, and thesecond wavelength conversion element comprises a second superstrate anda second lumiphoric material that is arranged between the secondsuperstrate and the second LED chip.